Destroying missiles, aircraft, re-entry vehicles and other targets falls into three primary classifications: “hit-to-kill” vehicles, blast fragmentation warheads, and kinetic energy rod warheads.
“Hit-to-kill” vehicles are typically launched into a position proximate a re-entry vehicle or other target via a missile such as the Patriot, Trident or MX missile. The kill vehicle is navigable and designed to strike the re-entry vehicle to render it inoperable. Countermeasures, however, can be used to avoid the “hit-to-kill” vehicle. Moreover, biological warfare bomblets and chemical warfare submunition payloads are carried by some “hit-to-kill” threats and one or more of these bomblets or chemical submunition payloads can survive and cause heavy casualties even if the “hit-to-kill” vehicle accurately strikes the target.
Blast fragmentation type warheads are designed to be carried by existing missiles. Blast fragmentation type warheads, unlike “hit-to-kill” vehicles, are not navigable. Instead, when the missile carrier reaches a position close to an enemy missile or other. target, a pre-made band of metal on the warhead is detonated and the pieces of metal are accelerated with high velocity and strike the target. The fragments, however, are not always effective at destroying the target and, again, biological bomblets and/or chemical submunition payloads survive and cause heavy casualties.
The textbooks by the inventor hereof, R. Lloyd, “Conventional Warhead Systems Physics and Engineering Design,” Progress in Astronautics and Aeronautics (AIAA) Book Series, Vol. 179, ISBN 1-56347-255-4, 1998, and “Physics of Direct Hit and Near Miss Warhead Technology”, Volume 194, ISBN 1-56347-473-5, incorporated herein by this reference, provide additional details concerning “hit-to-kill” vehicles and blast fragmentation type warheads. Chapter 5 and Chapter 3 of these textbooks propose a kinetic energy rod warhead.
The two primary advantages of a kinetic energy rod warhead is that 1) it does not rely on precise navigation as is the case with “hit-to-kill” vehicles and 2) it provides better penetration than blast fragmentation type warheads.
The primary components associated with a theoretical kinetic energy rod warhead are a projectile core or bay including a number of individual lengthy rod projectiles or penetrators, and an explosive charge. When the explosive charge is detonated, the rod projectiles or penetrators are deployed. Typically, these components are within a hull or housing.
Greater lethality is achieved when all of the rods are deployed to interrupt the target. In order to aim the projectiles in a specific direction, the explosive charge can be divided into a number of explosive charge segments or sections, with sympathetic shields between these segments. Each explosive segment may have its own detonator. Selected explosive charge segments are detonated to aim the projectiles in a specific direction and to control the spread pattern of the projectiles. For instance, detonators on one side of the projectile core can be detonated to cause their associated explosive charge segments to eject specified hull sections, creating an opening in the hull on the target side. Other detonators on the opposite side of the core are detonated to deploy the projectile rods in the direction of the opening and thus towards the target. See e.g. U.S. Pat. No. 6,598,534 and U.S. Pat. Publ. No. 20040055500A1 which are incorporated herein by reference.
While a kinetic energy warhead including the foregoing design may be highly effective, the exact position of the target in relation to the warhead explosive charge segments may affect aiming accuracy. The target may be positioned relative to the warhead such that the center of the rod set does not travel close to the target direction, resulting in aiming errors. For example, the target may be in a position where deploying one set of explosive segments, i.e. three adjacent segments, will result in the center of the rod core travelling in a direction which is not the target direction, but where deploying a different set of explosive segments, i.e. four adjacent segments, still may not direct the rods towards the target as desired. Additionally, the number of explosive segments detonated will affect the total spray pattern diameter, which may be critical in some applications.